Background Medical students are at the core of pandemic response as prospective health professionals. This study aimed to assess medical students’ knowledge, attitude, and practices toward the COVID-19 pandemic and measure their level of adaptation to infection control measures. Methods In this descriptive study, data was collected via an internet-based questionnaire delivered to students through e-mail between 19 August-14 September 2020. Participants were students enrolled in medical school in Istanbul, Turkey. Descriptive statistics and Chi-Square test were used to analyze data. Results Among 245 subjects enrolled in the study, the mean age was 21.8±1.7, and 58.0% were female, 49.0% were preclinical (1-2-3rd) grades. Most of the respondents (85.3%) thought they have enough knowledge; 97.6% knew about transmission routes. 31.8% of students used the World Health Organization website, 22% of the students used official government websites, and 20.0% of students used the news as a primary source for covid-related information. More than half of the students (60.8%) felt more anxious and nervous than usual due to pandemic, with female predominance. Over 85.0% of students fulfill infection control and preventive measures, such as wearing masks, washing hands, maintaining social distancing, and avoiding being in crowds. 68.2% of the students were following current guidelines prepared for COVID-19. We observed more frequent behaviors in students who report more anxiety and nervousness than usual. Most of the students (84.9%) expressed that they would be vaccinated when the vaccine is developed. Conclusions Mostly, medical students were well-informed with expected levels of knowledge, attitude, and preventive measures towards COVID-19. Anxiety-reducing interventions are urgently needed for medical students. Furthermore, pandemic management should be included in the medical school curriculum to increase knowledge, awareness, and protective behavior.